Leeds and Grenville Counties County, Ontario · Water Quality Report Card
Charleston Lake
Charleston Lake in Leeds and Grenville Counties, Ontario received a water quality grade of A (Excellent). Water clarity: 6 m visibility. Phosphorus: 9.6 µg/L.
- Clarity
- 6 m
- Type
- Oligotrophic
Charleston Lake is a cold, clear oligotrophic lake in Leeds and Grenville Counties County, Ontario. Water quality is graded A based on 2 sampling years through 2025. Compared to the 33 other monitored lakes in Leeds and Grenville Counties County, Charleston Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Ontario MECP, last sampled 2025-10-26. Grade methodology: LakeGrade methodology.
Watch Charleston Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 19.7 ft down. Phosphorus level: 9.6 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 m | A |
| Phosphorus | 9.6 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Charleston Lake
Compare lakeside cabins, hotels, and vacation rentals near Charleston Lake in Leeds and Grenville Counties, Ontario — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Charleston Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Charleston Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Charleston Lake — straight to your inbox. No spam, unsubscribe anytime.
Fishing Charleston Lake
Location
County Ranking
Ranked #5 of 34 lakes in Leeds and Grenville Counties
Nearby Lakes in Leeds and Grenville Counties
Explore Charleston Lake across LakeGrade
More Ontario Lake Rankings
Other Grade A Lakes in Ontario
Oligotrophic Lakes in Ontario
More records, surveys & data sources
Where this data comes from
Measurements for Charleston Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2025-10-26
Monitoring stations: